Encyclopedia/Botanical/TEM · Folk medicine/encyclopedia-horseradish

Horseradish

Armoracia rusticana

Sources

6 listed

Best forCooks who love a sharp condiment alongside boiled beef, smoked ham, or fish, and households that reach for a traditional Kren-Honig at the first signs of a cold.

Clinical evidence

Traditional

Real World Significance

69Established historical significance

Breadth 67 Depth 51 Density 63 Convergence 88 Continuity 90

SafetyUse with cautionSmall condiment amounts are usually tolerated but can cause symptoms in sensitive people. Medicinal preparations are unsuitable in gastric or intestinal ulcers, nephritis and known allergy. Children, pregnancy and breastfeeding require special restrictions. Concentrated topical applications can strongly irritate the skin.

Tradition

TEMFolk medicine

Common preparations

Fresh RootGeriebenTinctureSyrupBrei Poultice

In short

Summary of findings for quick reference

Horseradish is called Kren in Austria, a name borrowed from Slavic languages. The grated root has a long place in central European cooking and is also mixed with honey as a traditional cold remedy. Historical surveys describe medieval and early modern uses; ancient attributions remain uncertain because the plant identification is unclear.

The clinical evidence is for a combination, not for horseradish alone. The trials studied the fixed combination of horseradish root and nasturtium herb (Angocin Anti-Infekt N): Albrecht and colleagues in 2007 found fewer recurrent urinary infections in the per-protocol analysis, Stange and colleagues in 2017 reported responder rates similar to the antibiotic co-trimoxazole in acute cystitis but could not establish formal non-inferiority, and a 2023 trial showed faster symptom resolution in acute bronchitis. Single-herb horseradish evidence is limited to traditional use and in-vitro antibacterial work, so any benefit of the combination must not be credited to horseradish alone.

Commission E assessed horseradish root positively for respiratory catarrh, supportive urinary use and topical use for mild muscular pain; no EMA HMPC monograph exists. Medicinal preparations can irritate mucous membranes and are unsuitable in conditions including gastric or intestinal ulcers and nephritis. Children, pregnancy and breastfeeding require preparation-specific restrictions. Culinary and medicinal uses should be distinguished.

Clinical evidence ↔ Historical significance

We display two separate evidence categories: clinical evidence from modern trials and historical significance from documented healing tradition. Both are valuable, but they answer different questions.

In every encyclopedia entry we evaluate two distinct categories of evidence. Clinical evidence as used in trials meets a narrower but scientifically essential bar. At the same time, the hundreds of thousands of plant species worldwide have only partially been captured and tested in modern studies.

Alongside the trial picture our researchers compile a comprehensive overview of where and since when a plant has been used across different traditions of natural medicine. When a plant has been used as a medicinal plant in many cultures across many generations, that historical significance deserves to be visible too.

Our position: a truly informative overview emerges only when both categories sit side by side. We communicate transparently what counts as what.

Overview

Horseradish (Armoracia rusticana), called Kren in Austria, is a perennial root in the cabbage family (Brassicaceae) with a long, fleshy white taproot whose aroma only develops when the root is cut, grated, or chewed. The intact root is almost odourless; the moment the cells are broken, the enzyme myrosinase meets the stored glucosinolates (most importantly sinigrin) and releases pungent isothiocyanates, principally allyl isothiocyanate (AITC). The German Commission E gives horseradish root a positive monograph for catarrh of the upper respiratory tract, in support of mild urinary complaints, and topically as a rubefacient for mild muscular complaints. There is no EMA HMPC or ESCOP monograph for horseradish root, so the German Commission E is the standing regulatory anchor.

In Austria, Kren is a classic condiment for dishes such as boiled beef or a cold snack. Cultivation is concentrated in Styria. Grated root with honey is also a traditional cold remedy. Clinical studies mainly concern Angocin Anti-Infekt N, a horseradish-root/nasturtium-herb combination, for respiratory and urinary infections. Its findings do not establish the same effect for the root alone. Mustard oils provide the pungency but can also irritate mucous membranes.

History

Horseradish originates in eastern Europe and has been used in central Europe as a condiment and medicinal plant for centuries. Ancient names such as Pliny’s Amoracia cannot be securely equated with modern horseradish. Historical surveys describe medieval use and accounts in Renaissance herbals, but the beginnings of individual uses are not consistently documented.

Horseradish is firmly established in Austrian and Hungarian cooking. Austrian commercial production is concentrated in Styria. Freshly grated root with honey is also a traditional cold remedy. Modern phytotherapy research mainly concerns the root combined with nasturtium herb. In Germany, Angocin Anti-Infekt N is licensed to improve symptoms of acute inflammatory conditions of the bronchi, sinuses and draining urinary tract. Commission E assessed the root positively in 1988; there is no EMA HMPC or ESCOP monograph.

Mechanism

The signature chemistry of horseradish starts with the glucosinolates stored in the intact root, most importantly sinigrin (which yields allyl isothiocyanate or AITC) and gluconasturtiin (which yields phenylethyl isothiocyanate or PEITC). On their own these compounds are odourless and stable; the moment the root is cut, grated, or chewed, the enzyme myrosinase comes into contact with the glucosinolates and releases the volatile isothiocyanates within seconds. AITC is responsible for the characteristic sharp, sinus-clearing bite. The same enzymatic conversion runs in mustard, wasabi, and to a lesser extent in radish; it is the defining chemistry of the Brassicaceae.

Allyl isothiocyanate shows antimicrobial activity in laboratory studies. After absorption, isothiocyanates are metabolised and mainly eliminated in urine; release in exhaled air has also been described. This alone does not establish that horseradish treats an infection. Topically, mustard oils irritate the skin and increase local blood flow, producing redness and warmth; excessive concentrations can cause painful irritation.

Clinical research mainly concerns Angocin Anti-Infekt N, a fixed combination of horseradish root and nasturtium herb. A 2007 placebo-controlled trial examined recurrent UTI prevention. A 2017 acute uncomplicated cystitis trial compared the product with co-trimoxazole but did not demonstrate non-inferiority and was stopped early because of slow recruitment. A 2023 placebo-controlled study in 384 patients found faster bronchitis symptom improvement. Open comparisons add context but do not establish equivalence to antibiotics.

Clinical evidence for horseradish alone is limited. The cited trials studied a combination product, so their findings do not establish efficacy of the single root or homemade horseradish with honey. The Commission E monograph describes traditional medicinal uses; no EMA HMPC or ESCOP monograph exists. Horseradish is established in Austrian cooking, but a home remedy should not replace necessary medical treatment.

Evidence

4 Outcomes evaluated. Sorted by grade.

Outcome	Class	Grade	Effect	Refs
Symptoms of common cold and upper respiratory tract infectionAdults with uncomplicated URTI; combination preparation with nasturtium herb	Traditional	C	Traditional Use	[3]
Mild urinary complaintsAdults with uncomplicated UTI; combination with nasturtium herb	Traditional	C	Traditional Use	[1][2]
Mild muscular complaints (topical use)Adults; topical rubefacient preparations	Traditional	C	Traditional Use	[6]
Mucosal irritation and gastrointestinal complaintsParticularly with medicinal preparations; individual tolerance as a condiment also matters	Insufficient	I	Irritation as a possible adverse effect	[4][6]

Usage

Forms and preparation

For cooking, peel a piece of fresh horseradish and grate it finely just before serving. Crushing releases its pungent mustard oils. Mix with grated apple for Apfelkren or with whipped cream for Oberskren; a little vinegar also works well. Prepare only what you need, as the aroma fades after grating. Kren-Honig is traditionally made from finely grated fresh root and honey. It has no established clinical dose, and tolerance depends on the amount and pungency. For topical use, choose a preparation intended for that purpose and seek pharmacy advice. Homemade undiluted grated-root paste can strongly irritate the skin; stop immediately if it burns or hurts.

Dosage

Use horseradish as a condiment according to taste and tolerance; this does not define a medicinal dose. Homemade Kren-Honig has no established clinical dosing regimen. Pharmaceutical references give 20 g fresh root as a medicinal daily amount, not a general culinary recommendation or a teaspoon rule transferable to every preparation. The HMPPA monograph recommends limiting medicinal oral use to no more than four weeks because mucous membranes may be irritated. For combination medicines, follow the leaflet and medical advice; instructions may differ by product and country. Topical use calls for suitable diluted preparations; a universally safe exposure time for homemade grated-root compresses is not established. Seek prompt medical assessment for breathlessness, fever, blood in urine or flank pain, and for persistent or worsening symptoms.

Safety

Safety profile

Mustard oils can irritate mucous membranes. Do not take horseradish medicinally if you have gastric or intestinal ulcers, nephritis or known allergy. Discuss tolerance first if you have gastritis, reflux or other gastrointestinal problems. General herbal references advise against medicinal root use under age four; Angocin Anti-Infekt N has its own age limit of six years, with medical advice required for children aged six to twelve. The Austrian Angocin Anti-Infekt Uro+Grippal has different particulars: for colds from age six, and for uncomplicated cystitis in adult women. Girls from age twelve may use it for cystitis only after medical assessment. Men and all children and adolescents with urinary symptoms need medical advice. Discuss medicinal use first if you take regular medication or have a chronic condition. Because of its nasturtium component, Angocin may affect anticoagulants such as phenprocoumon or warfarin, which are vitamin-K antagonists. Blood clotting requires close medical monitoring when they are taken together. Safety data for medicinal use in pregnancy and breastfeeding are insufficient. Do not apply undiluted root paste to sensitive or damaged skin, mucous membranes or open wounds.

Look-alikes

Botany

Family

Brassicaceae

Native regions

Eastern Europe (native range), Temperate Asia (cultivated and naturalised), Austria (cultivation concentrated in Styria), Slovenia, Hungary, Czechia (traditional cultivation), Naturalised across central and northern Europe

Harvest window

Roots harvested in autumn and through winter into early spring when the soil is workable.

Habitat

Deep, well-drained, moist loam in sun to partial shade. Horseradish needs room for its strong roots. It originates in eastern Europe and is naturalised across much of central and northern Europe. Austrian cultivation is concentrated in Styria, particularly the south and east of the province.

Identification & foraging

A robust perennial of the cabbage family, fifty to one hundred and twenty centimetres tall. Large, long-oval to lance-shaped basal leaves with a coarsely toothed margin; the leaves can be more than half a metre long in a mature plant. Small white flowers in loose racemes typical of the Brassicaceae, with four petals arranged in a cross. The defining feature is the long, white, fleshy taproot with its sharp, sinus-clearing aroma the moment the surface is cut; the intact root has almost no smell. The plant rarely sets viable seed in cultivation and is propagated by root cuttings.

FAQs

How do I make Kren-Honig at home?

For Kren-Honig, finely grate a small piece of fresh horseradish and mix with honey. Prepare only a small amount and check your tolerance cautiously. This is a traditional cold remedy without an established clinical dose; Angocin trial results cannot be transferred to this mixture.

Can I take Kren-Honig if I have a stomach ulcer?

No. Do not take horseradish medicinally if you have a gastric or intestinal ulcer; its mustard oils can further irritate the lining. Pungency can also aggravate gastritis or reflux symptoms, and a small condiment amount is not automatically tolerable for everyone. Discuss use with your doctor if you have gastrointestinal problems.

Can I grow Kren in my garden?

Yes. Horseradish needs deep, well-drained soil and spreads readily from root pieces. Plant root cuttings in spring according to the supplier’s instructions. Give it its own bed because small pieces left behind can regrow. Harvest in autumn or, while the soil remains workable, into spring.

How sharp is too sharp?

Tolerance varies. Start with a small amount as a condiment. Persistent throat burning or stomach discomfort means it was too much for you. Honey, apple or cream may soften the taste but do not reliably prevent irritation. Avoid horseradish if even small amounts cause lasting symptoms.

References

6 sources.

Uwe Albrecht, Karl-Heinz Goos, Berthold Schneider. A randomised, double-blind, placebo-controlled trial of a herbal medicinal product containing Tropaeoli majoris herba (Nasturtium) and Armoraciae rusticanae radix (Horseradish) for the prophylactic treatment of patients with chronically recurrent lower urinary tract infections. 2007. doi:10.1185/030079907X233089
Rainer Stange, Berthold Schneider, Uwe Albrecht, Valentina Mueller, Joerg Schnitker, Andreas Michalsen. Results of a randomized, prospective, double-dummy, double-blind trial to compare efficacy and safety of a herbal combination containing Tropaeoli majoris herba and Armoraciae rusticanae radix with co-trimoxazole in patients with acute and uncomplicated cystitis. 2017. doi:10.2147/RRU.S121203
Uwe Albrecht, Ulrich Stefenelli, Rainer Stange. A combination of Tropaeolum majus herb and Armoracia rusticana root for the treatment of acute bronchitis. 2023. doi:10.1016/j.phymed.2023.154838
Repha GmbH. ANGOCIN Anti-Infekt N: Gebrauchsinformation. 2020. Source
Repha GmbH; Bundesamt für Sicherheit im Gesundheitswesen (BASG). ANGOCIN Anti-Infekt Uro+Grippal: Gebrauchsinformation, Reg.Nr. 740866. 2025. Source
Arnold Achmüller, Rudolf Bauer, Chlodwig Franz, Brigitte Kopp, Hermann Stuppner. Meerrettich: HMPPA-Monographien, Pflanzliche Naturstoffe im Profil. 2023. Source

Legal notice: The depiction of historical significance and traditional use is context within our encyclopedia and not a health claim for any product, not a treatment promise, and not a substitute for medical advice. What may be stated on product labels, product pages, or in advertising is governed by the applicable legal requirements.